The payback, ordered by a panel set up by David Cameron, brings to £255,000 the total amount of expenses returned to the Commons authorities by Conservative MPs. Nine Tories have agreed to forgo their “second homes” allowance, saving taxpayers £108,000.

It means that 90 Tories, almost half the party’s 193 MPs, have made repayments or stopped claiming. The scrutiny panel has now investigated the payments made to 188 of them.

Eight Tory backbenchers have already announced they will quit Parliament at the next election following criticism of their expenses. Yesterday, Mr Cameron said he expected others to follow suit after reflecting on their positions.

The Tory leader won the backing of his MPs for his crackdown on expenses when he addressed them yesterday and admitted that the process was difficult and painful.

Privately, however, many Tories are angry about his tough stance and the “rough justice” it has administered. Some accuse him of “Stalinist” tactics and using the expenses crisis as an excuse to force out Tory grandees to boost his drive to change the party’s image.

Among the new repayments announced yesterday were £25,000 in capital gains tax by the shadow Justice Minister Eleanor Laing, who made a reported £1m profit on the sale of a second home, which she switched to her main residence.

Sir John Butterfill, the MP for Bournemouth West, is to pay back a further £14,478 relating to claims for mortgage interest and council tax on an annexe to his house used as servants’ quarters. He had already repaid £3,000.

Sir Peter Viggers, who had a claim for a floating duck house rejected, will repay £10,000 in claims for garden maintenance and repairs.

Bill Cash, the prominent Eurosceptic, agreed to repay £15,000 in second home allowance he claimed to pay his daughter for renting her London flat, while his son lived in the MP’s own apartment.

David Heathcoat-Amory, a former Europe Minister who claimed for hundreds of pounds worth of horse manure, will repay £5,000 of gardening expenses. John Gummer, the former Environment Secretary, who claimed for removing moles from his garden, is to repay £11,538 received for gardening and household expenses.

Repayments by Andrew Mackay, Mr Cameron’s former aide, and backbencher Brian Binley have been deferred because their cases are being investigated by Parliament’s anti-sleaze watchdog.

Mr Cameron said his party was trying to “atone for the past”. He added: “The fact that MPs have chosen to make repayments does not indicate guilt or a breach of the rules. The vast majority of MPs do an excellent job. But we recognise public anger about expenses, and we have a duty to listen and respond to it. That is what this is about.”

The Conservative leader admitted that the panel’s review had not been a “perfect process” and there would be inconsistencies. “In some cases it may have been too tough. In others, some may feel it has not been tough enough,” he said.

Gordon Brown announced yesterday that Labour’s election candidates had been ordered to sign a pledge to uphold “high standards of integrity” as part of the party’s attempts to clean up politics.

The Prime Minister told a meeting of prospective candidates and young activists it was vital to show that politicians understood the standards voters required of them. The pledge, which is expected to extend to sitting MPs, promises “prudence with public money”, to comply with all Commons rules and to publish all allowances online.

A survey of 1,140 adults by the PoliticsHome website last month found that three-quarters believed that repayments by MPs would make no difference to the way they would vote and suggested the move could be seen as an admission of guilt.

The Parliamentary authorities said last week that 182 MPs from all parties had repaid £478,616 in expenses since the crisis erupted last month. Their figures showed that Labour MPs had paid back £316,027, while the Liberal Democrats have repaid £27,082.

However, the Commons figures were withdrawn to be “updated” after errors were found. Eight names had wrongly been added to the list, which included an MP called “Richard Packer” who does not exist.